The present invention relates to an optical transmitter-receiver module and an electronic device for use in a single-core bidirectional optical transmitter-receiver system capable of performing transmission and reception with a single-core optical fiber. The present invention relates, in particular, to a digital communication system, which is able to perform high-speed transmission, such as IEEE1394 (Institute of Electrical and Electronic Engineers 1394) and USB (Universal Serial Bus) 2.0. The present invention also relates to a method of manufacturing the optical transmitter-receiver module.
Conventionally, as a first optical transmitter-receiver module, there is a one as described in Japanese Patent Laid-Open Publication No. 2001-116961. In this optical transmitter-receiver module, full-duplex communications are achieved by reducing electric crosstalk by employing a shield plate while reducing optical crosstalk by employing a light-tight partition plate that abuts against the end surface of the optical fiber so as to separate the light-emitting device and the light-receiving device from each other.
FIG. 35A and FIG. 36A are plan views of a partition plate 1019, while FIG. 35B and FIG. 36B are side views showing the positional relationship of the partition plate 1019 with respect to an optical plug 1030. With regard to this first optical transmitter-receiver module, FIGS. 35A and 35B shows a state in which the optical plug 1030 provided internally with a single-core optical fiber 1032 is partway inserted in an optical transmitter-receiver module (overall view is not shown) and starts coming in contact with the partition plate 1019. FIGS. 36A and 36B show a state in which the optical plug 1030 is completely inserted in the optical transmitter-receiver module and fully put in contact with the partition plate 1019.
FIG. 37A shows a side view of an essential part of an optical cable, which has the plug 1030 and constitutes an optical transmitter-receiver system with the aforementioned optical transmitter-receiver module, while FIG. 37B shows a rear view of the optical cable that has the optical plug 1030. As shown in FIGS. 37A and 37B, the optical plug 1030 (including the optical fiber) is provided at each end portion (only one end portion is shown) of the optical cable, and a front end of the optical plug 1030, which includes a tip of the optical fiber, has an inclined surface 1030a inclined forward in the lengthwise direction of the optical fiber (i.e., toward the other optical transmitter-receiver module side not shown). Moreover, the optical plug 1030 is provided with a anti-rotation key 1031 extended in the horizontal direction, and the optical transmitter-receiver module is internally provided with a keyway (not shown) that cooperates with the key 1031, for preventing possible changes in the optical input and characteristics in accordance with the rotation of the optical plug 1030.
Moreover, as a second conventional optical transmitter-receiver module, there is a one as described in Japanese Patent Laid-Open Publication No. 2001-147349. As shown in FIG. 38, this second optical transmitter-receiver module employs a partition plate 1111 similar to that of the aforementioned first conventional optical transmitter-receiver module that has an optical system employing a Foucault prism 1104. According to this, in the second optical transmitter-receiver module, the end surface of the optical fiber 1102 of the optical plug 1101 abuts against the partition plate 1111, and a light-emitting element 1103 and a light-receiving element 1105 are molded or encapsulated with a molding resin 1106. Lens portions 1106a and 1106b are integrally formed in the plastic molding stage of the molding resin.
In the aforementioned first conventional optical transmitter-receiver module, the optical plug 1030 has the anti-rotation key 1031. Therefore, the optical plug 1030 cannot be inserted into the optical transmitter-receiver module unless the key 1031 is aligned with the keyway of the optical transmitter-receiver module when fitting the optical plug 1030, and this disadvantageously causes inconvenience to the user. However, if the anti-rotation key 1031 of the optical plug 1030 is removed to improve the convenience at the time of insertion of the optical plug, then the optical plug 1030 becomes rotatable. Therefore, if the optical plug 1030 rotates with an optical fiber end surface 1030a being in contact with the partition plate 1019, then there occurs a problem that the inclined end surface 1030a of the optical fiber and/or the partition plate 1019 is damaged.
Moreover, the second conventional optical transmitter-receiver module, which employs the Foucault prism optical system having the partition plate 1111 similar to that of the first conventional optical transmitter-receiver module, has the structure in which the partition plate 1111 abuts against the end surface of the optical fiber 1102. Therefore, similarly to the first conventional optical transmitter-receiver module, there occurs a problem that the end surface of the optical fiber 1102 and/or the partition plate 1111 is damaged. Furthermore, the light-emitting element 1103 and the light-receiving element 1105 are mounted on an identical substrate 1109 in this second optical transmitter-receiver module, but the optical positions of the light-emitting element 1103 and the light-receiving element 1105 are not optimized with regard to the optical system that has the partition plate 1111.